Ionic Radius Trends and Multiple Ionization Energies

Ionic radius trends

Multiple Ionization Energies​

Bromfield Honors Chemistry

negatively charged ions

form when atoms GAIN electrons

​Anions

positively charged ions​

form when atoms LOSE electrons

​Cations

Ions

Some text here about the topic of discussion

negatively charged ions

form when atoms GAIN electrons

​Anions

positively charged ions​

form when atoms LOSE electrons

​Cations

Ions

Some text here about the topic of discussion

​Ionic radius trends

Cations typically have a SMALLER radius than the parent atom

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​Cations vs parent ion

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Cations typically have a SMALLER radius than the parent atom

​

• Fewer electrons

• Fewer electron:electron repulsions

• Fewer occupied energy levels

Anions typically have a larger radius than the parent ion​

​Anions vs parent ion

​r

​Some text here about the topic of discussion.

More electron-electron repulsions​

​Anions typically have a larger radius than the parent atom

​r

What is the trend down a group?

What is the trend across a period?​

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​Ionic radius trends

Ionic radius increases down a group​

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​Ionic radius trends

Ionic radius decreases from L --> R for cations

Jumps up for anions, then decreases​

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​Ionic radius trends

Multiple Choice

Which of the following would have the larger radius?

• Ca

• Ca²⁺

Multiple Choice

Which of the following would have the larger radius?

• P

• P^3-

Multiple Choice

Which of the following would have the larger radius?

• Ca²⁺

• Cl^-

Multiple Choice

Which of the following would have the larger radius?

• K⁺

• Sc³⁺

Multiple Choice

Which of the following would have the larger radius?

• Cl^-

• I^-

Multiple Choice

Which of the following would have the larger radius?

• P^3-

• S^2-

Multiple Ionization Energies

First ionization energy

• The energy required to remove the outermost electron from an isolated gas phase atom

Multiple Choice

The equation for the first ionization energy of a sodium atom is:

• Na (g) + IE ⟶ Na⁺ (g) + e^-

• Na⁺ (g) + IE ⟶ Na²⁺ (g) + e^-

• Na⁺ (g) + e^- ⟶ Na (g) + IE

Second ionization energy

• The energy required to remove a second electron

Multiple Choice

The equation for the second ionization energy of a sodium atom is:

• Na (g) + IE ⟶ Na⁺ (g) + e^-

• Na⁺ (g) + IE ⟶ Na²⁺ (g) + e^-

• Na⁺ (g) + e^- ⟶ Na (g) + IE

Successive ionization energies

• You can have as many ionization energies as there are electrons in the neutral atom

• This graph shows the first 7 ionization energies for sodium

• As you remove more and more electrons, it takes more and more ionization energy

Open Ended

Why do you think successive ionization energies increase as additional electrons are removed? Hint: Consider electron configurations in your answer.

Sodium

• Consider the values for the first and second ionization energies of sodium

Multiple Choice

When a neutral atom of sodium loses its first electron, the electron is removed from the ____ sublevel.

• 1s

• 2s

• 2p

• 3s

Multiple Choice

When a Na⁺ ion loses an electron, the electron is removed from the ____ sublevel.

• 1s

• 2s

• 2p

• 3s

Open Ended

Compare the magnitude of the first and second ionization energies of sodium.

Removing a second electron from Na

• Removing the first electron from Na is relatively easy

• To remove a second electron from Na, we have to remove an electron from a noble gas-like electron configuration

Removing a second electron from Na

• We see a BIG jump in IE values once all the valence electrons have been removed

Multiple Choice

Why do we see a big jump in Ionization energy?

• Because once an element loses all of their electrons there is no more to take

• Because once an atom loses all their valence electrons, it is harder to take them away

• Because once the atom becomes an ion it is harder to take electrons away

• Because once the atom loses 8 electrons it is harder to take them away

Successive IE values for Mg

• IE₂ > IE₁, as expected

• We see a big jump between IE₂ and IE₃

Successive IE values for Mg

• Removing both electrons from the 3s sublevel is relatively easy

• Once we try to remove an electron from a fully filled energy level, it takes a LOT more energy!

• This confirms 2 valence electrons for Mg

Multiple Choice

Successive ionization energies for an element in Period 4 were found to be:

IE₁=600 kJ/mol

IE₂=1800 kJ/mol

IE₃=2700 kJ/mol

IE₄=11,600 kJ/mol

IE₅=15,000 kJ/mol

How many valence electrons does this element have?

• 1

• 2

• 3

• 4

• 5

Multiple Choice

Successive ionization energies for an element in Period 4 were found to be:

IE₁=600 kJ/mol

IE₂=1800 kJ/mol

IE₃=2700 kJ/mol

IE₄=11,600 kJ/mol

IE₅=15,000 kJ/mol.

Identify the element:

• germanium

• selenium

• gallium

• silicon

• phosphorous